1. Field of the Invention
This invention relates to novel polymers and copolymers of acrylamide and to methods for their preparation.
2. Description of the Prior Art
The polymerization of acrylamide alone or with ethylenically unsaturated monomers in the presence of catalysts of the free radical type or redox type or in the presence of radiation is well known. Typical of such catalyst systems are the following described in the indicated references.
______________________________________ Catalyst System Reference ______________________________________ thioureaogen Peroxide - Cu.sup.++ USP # 3,255,072 2. Ammonium persulfate - Sodium metabisulfite - EDTA USP # 3,442,803 3. Potassium persulfate - Fe.sup.++ Metabisulfite USP # 3,316,181 4. Ammonium persulfate - Cu.sup.++ Sodium bisulfite USP # 3,332,922 5. Potassium persulfate - Sodium metabisulfite USP # 3,450,680 6. Sodium bromate - (Pat. No. unknown) Sodium sulfite 7. Ammonium persulfate - nitrilotrispropionamide USP # 3,002,960 8. Free radicals So. Africa Patent 69-1, 065/969 9. Spray drying of catalyst USP # 3,644,305 10. Co.sup.60 - gamma ray Brit. Pats. 1,139,917/ 1969 and 1,337,109/1973 11. Co.sup.60 - gamma ray or presence of systems: benzoil peroxide - N,N'- dimethylaniline; t. - butylhydroper- dimethylaniline' Chemical Abstracts 1969 12. Co.sup.60 - gamma ray or in the presence of complex of potassium diaquodioxalo manganese USP # 3,736,241 {K [ Mn (C.sub.2 O.sub.4).sub.2 (H.sub.2 O).sub.2 ]} ______________________________________
The above described catalyst systems are not without their shortcomings, however, in polymerization reactions involving acrylamide. First of all, the presence of air cannot be tolerated in acrylamide polymerizations employing these catalyst systems for the excess oxygen prematurely terminates the reaction resulting in a final product having an undesirably low molecular weight. Consequently, it is necessary with these catalyst systems to either evacuate the reaction vessel of air prior to initiating the polymerization or to effect the polymerization in the presence of an inert gas such as nitrogen or argon.
Other disadvantages associated with these catalysts is the fact that the conversion is less than one hundred percent and the time of reaction is unduly long, requiring in general in excess of twelve hours.
A further objection, in addition to the inert atmosphere required, to the use in acrylamide polymerizations of the initiator complex described in U.S. Pat. No. 3,736,241 for the polymerization of acrylonitrile is that the catalyst decomposes to evolve noxious carbon monoxide.